Injection pump



Jan. l, 1952 V, J, JANDASEK 2,580,785

\ INJECTION PUMP Filed Oct. 29, 1945 2 SHEETS-SHEET l l/c nouw/p d. c/mvonsek QTTOENEY Janl 1952 v. .1. JANDASEK 2,580,785

v INJECTION PUMP Filed oct. 29, 1945 2 SHEETS-Smm 2 IN V EN TOR. lnaw lc/Nansen B Y A .4

Patented Jan. 1, 1952 INJECTION PUMP Vladimir J. Jandasek, Detroit, Mich., assignor to Bendix Aviation Corporation, Detroit, Mich., a

corporation of Delaware Application October 29, 1945, Serial No. 625,305

(Cl. S-.2)

5 Claims. l

This invention relates to pumps, and more particularly to Aa single plunger fuel injection pump.

The invention comprises a single plunger for the distribution and injection of fuel into a plurality of cylinders. The plunger has both a reciprocating and a rotating motion, the former generating the required injection pressure and the latter distributing the fuel to the proper cylinder.

At the present time. a four cylinder injection pump in a small size suitable for automotive installation costs the engine manufacturer considerably more than the cost of the rest of the engine. A single plunger pump provides for a considerable reduction in the cost of injection equipment by permitting a large reduction in the number of parts. Thus, the cost of the plunger and barrel assemblies, ordinarily high due to the required lapping to extremely close tolerances,

is reduced to a minimum.

A by-pass sleeve which is moved axially on the plunger controls the amount of fuel injected into the cylinders. Since the same ports are used for all the cylinders, by virtue of the single plunger, it is possible to maintain a very uniform fuel delivery to all of the cylinders throughout the operating range of the pump.

The invention has a general application. It

may be used for stationary, automotive or aircraft installations using either fuel oil or gasoline at either low or high pressures. In aircraft installations, the single plunger injection pump would afford a weight reduction advantage.

An object of the invention is to provide means for injecting fuel under pressure into two or more cylinders by using a single plunger.

Another object of the invention is to provide a pump which, by a reciprocating and rotating motion of a single plunger, injects fuel into two or more cylinders.

Another object of the invention is to provide a single plunger fuel injection pump for two or more cylinders. said plunger having a reciprocating motion imparted by a camshaft geared to the driving shaft, and a rotating motion imparted by the driving shaft through suitable gearing means. Y A further object of the invention is to provide an injection pump with a single plunger having a helical slot in the upper or distributing portion of the plunger which successively registers with the delivery ports .of two or more cylinders upon rotation of the plunger.

Still a further object of the invention is to provide a fue1 injection pump having a single plunger 2 with a distributing portion helically slotted. the angle of helix being determined by the reciprocating and rotating motions of the plunger.

And still a further object of the invention is to provide a single plunger fuel injection pump having an axially adjustable sleeve as part of the pump cylinder wall for metering fuel to two or more cylinders.

Another object of the invention is to provide a fuel injection pump for two or more cylinders which is simply and compactly constructed, substantially low in production cost, suitable for a wide variety of uses, and which will maintain a high degree of uniformity in fuel delivery.

These and other objects, features, and advantages of the invention will appear to those skilled in the art from the following description and accompanying drawing, wherein-` Fig. 1 is a top plan view of an injection pump embodying the invention;

Fig. 2 is a sectional view in elevation of the Pump;

Fig. 3 is a side view in elevation of the pump; and

Fig. 4 is a view in section of the opposite side of the pump shown in Fig. 3.

Referring to the drawing for more specific details of the invention, I0 represents an engine driven shaft having a flange I2 and a sleeve I4 suitably connected to a pump driving shaft I6 by a nut I8.

The shaft i6 is supported for rotation by bearings 20 fitted between the shaft and a gear housing 22, said housing having therein a semiannular space 24 containing a gear 26 held for rotation with shaft I6 by a key. 'Ihe gear .26 engages a gear 28 secured by a key to a camshaft 30 which extends into a pump housing 32 and is supported for rotation therein by bearings.

A camshaft chamber 34 within the pump housing 32 has therein a cam 36 on the camshaft 30. said cam engaging a flange 38 on the lower end of a plunger 40.

Sections 42 and 44 of the pump housing 32 have therethrough a cylindrical bore for the reception of the plunger 40, and between the said sections is a gear 46 keyed to the plunger by a pin 48 tting in a slot in said plunger. The pin 48 allows no relative rotation between the gear 46 and the plunger 40, but does allow the plunger to move with a reciprocating motion for a distance equal to the length of the slot. Sections 42 and 44 of the pump housing prevent the axial movement of the gear 46.

A gear 50 keyed to the pump driving shaft I6 3 engages the gear 4l on the plunger 40 so as to impart a rotating motion to the plunger. The pump driving shaft I has a free end supported for rotation by bearings within the housing 52.

The plunger 40 has a slot for the reception of a key on a portion 54 of the plunger. The above the portion 54 consists of a triple diametral shaft. the small diameter section 56 being rigidly connected to the portion 40. The shaft section 00 extends through an annular ring 58 having a plurality of shoulders, said ring not being in contact with the shaft section 50 but being supported by the portion 04.

The multi-shouldered ring l0 supports on its lowest shoulder a spring 00 which in turn supports at the upper end thereof a drum 02 enclosing a fuel metering mechanism, said drum being suitably secured to a flange I4 of a sleeve 60 having on the outer surface of the sleeve portion threads and having on the inner surface of the sleeve portion splines 0l meshing with splines 10 of a by-pass sleeve 12, thus securing said by-pass sleeve against rotation relative to the sleeve 66. Sleeve 00 is in turn secured against rotation by a key between the flange 04 and a wall section 14 of the pump housing.

The entire assembly within the drum 02 is supported by the spring 60 and is prevented by said spring from any tendency to move in the reciprocating manner of plunger 40. The tendency of the drum-enclosed assembly to rotate is prevented by the key between the flange $4 and the wall section 14.

The by-pass sleeve 12 extends upwardly through a circular bore in the wall section 14, the intervening space between said wall section and the by-pass sleeve being effectively sealed by a rubber sealing means 10.

The by-pass sleeve has at the lower end thereof threads which are engaged by threads on the flange portion of a by-pass control sleeve l0. On the inner surface of the upper portion of the by-pass control sleeve 00 are threads which engage threads on the sleeve 00, while a gear l2 on the outer surface of the sleeve 00 is connected through gearing means, not shown, to a lever 04 for purposes which will hereinafter appear.

An annular chamber 8S, constituting a fuel reservoir, is defined by the outer walls of the pump housing. the by-pass sleeve 12, and a circular plate Il having a hub 00 and a drilled hole 02 through the hub, said hole being the cylinder inlet port. The annular space 04 between the hub 00 and the by-pass sleeve 12 constitutes a cut-off relief for the cylinder.

The larger diameter portion of the plunger 40 fits very closely within a cylinder wall defined by the inner surfaces of the by-pass sleeve 12, the hub 00. and a head section 00 of the pump housing.

Registering with the cylinder inlet port 02 when the plunger is at the bottom of its stroke, is a chamfered portion 90 of the plunger having passages |00 leading into a cylindrical bore |02 within the plunger, said bore serving as a pressure chamber for the fuel during a compression stroke. A similar chamfered surface |04 having passages |00 leading to the cylindrical bore |02 is located below the chamfered portion 90 of the plunger 40 a distance slightly greater than the length of stroke of the plunger.

Above the chamfered portion 90 of the plunger 40 is a distributing portion of the plunger having a helical slot |00 which, upon rotation of the plunger and consequent intermittent registering of said slot with the cylinderoutlet ports ||0 alplunger lows the fluid under pressure within the cylindrical bore |02 of the plunger to pass from the bore through the slot and into said outlet ports H0.

The upper portion ||2 of the cylinder allows for the stroke of the plunger, and a threaded plug I |4 serves as the upper end of the cylinder chamber.

The cylinder outlet ports I0, having been formed by a drillingvoperation through the upper portion of the pump housing, have their outer ends stoppered by threaded bolts IIC. The outlet ports ||0 lead upwardly through passages H0 to spring-loaded check valves |20.

The gear housing 22 is suitably secured to the pump housing 02, by suitable bolts, while a housing |22 suitably attached to the pump housing has a sleeved arm |24 supporting for rotation the end of camshaft 30, said camshaft having splined on the end thereof a governor |20 having arms |20 adapted to pivot outwardly to control the speed of the camshaft. A nut on the threaded end of the camshaft secures the governor in place.

The pump operates in the following manner.

` Power is transmitted by the engine through the engine driven shaft l0 to the pump driving shaft li. Shaft i6 imparts a rotating motion to the plunger 40 through the engagement of the gear 50 on the shaft I6 and the gear 40 on the plunger 4I. At the same time, the shaft I6 turns the gear 20 which in turn causes the gear 20 on the camshaft 20 to revolve, thus imparting a rotating motion to the camshaft and a reciprocating motion to the plunger 40 through the engagement of the flange Il on the plunger with the cam 30 on the camshaft 30.

Gear 20 is four times the diameter of gear 20 on the camshaft 00, thus causing the camshaft to make four revolutions for every one revolution of the pump driving shaft I0. Plunger 40 makes one revolution each time the pump driving shaft I0 revolves once. Thus, plunger 40 makes four complete strokes every time it revolves once.

In Fig. 4, the plunger 40 is at the bottom of the down-stroke preparatory to a compression stroke. Liquid fuel from the fuel reservoir 0i, under a slight vacuum resulting from the decompression stroke of the plunger, flows through the passages |00 in the chamfered portion 92 of the plunger into the cylindrical bore |02 within said plunger, filling the bore |02 and the cylinder space I2 above the plunger.

As the plunger starts the up-stroke, the niiet port 02 no longer registers with the chamfered portion of the plunger, and the fuel is placed under pressure.

When pressure is applied to the fuel, injection takes place into one cylinder only during one stroke of the plunger. This is accomplished through the registering of the helical slot |00 with one of the cylinder outlet ports ||0 during the turning of the plunger in the compression stroke. As the plunger turns, the slot |02, due to its helical nature, remains in registry with a single cylinder outlet port ||0 during a single 'I up-stroke of the plunger. During the following up-stroke the slot registers with a succeeding outlet port, until, after four complete strokes of the plunger and one concurrent revolution of said plunger, fuel has been injected into each of the four cylinders.

Injection continues to take place after the sealing of the inlet port $2, until the chamfered portion |04 of the plunger 40 registers with the by, pass channel 04, whereupon the fuel is no longer under compression in the cylinder bore |02.

During the compression stroke, the fuel passes fromA the cylindrical bore |02 of the plunger through the helical slot |08 and one of the cylinder outlet ports H0, and through a passage H8 into the valve and therethrough into the engine cylinder.

The amount ofv fuel injected into an engine cylinder can be increased or decreased by the movement of the lever 84 which acts through suitable means, including the gear 82 on the sleeve 80 within the drum 62, to turn the sleeve 80 in one direction, and causes the said sleeve to move either up or down on the threads of the flanged sleeve 66. Since the threads on the by-pass sleeve 'I2 are of opposite hand to the threads on the sleeve 66, a movement of sleeve 80 causes a movement in the opposite direction of by-pass sleeve l2.

`When the by-pass sleeve is lowered by the aforementioned process, the distance the plunger has to move in an upward direction before the end of injection takes place upon the registering of the chamfered portion |04 of the plunger 40 with the passage 94 is decreased, -thus lessening the length of power stroke, and consequently, the amount of fuel injected during a stroke of the plunger 40.

During the pressure stroke of the plunger 40, the spring 60 is compressed, and this spring serves to keep the plunger in contact with the cam 36 during the down-stroke of the plunger.

While this invention has been described in connection with certain specific embodiments, the principle involved is susceptible of numerous other applications that will readily occur to persons skilled in the art. The invention is, therefore, to be limited only as indicated by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is:

1. A fuel injection pump comprising a reservoir, a cylinder extended therethrough having an intake port in direct communication with the reservoir and spaced discharge ports, a piston in the cylinder having a distributing portion including a helical slot adapted to register with the ldischarge ports in sequence, and means for reciprocating and rotating the piston.

2. A fuel injection pump comprising a reservoir, a cylinder extended therethrough having an intakeport in direct communication with the reservoir and spaced discharge ports, a piston in the cylinder having a chamber adapted to communicate with the intake port and a helical groove communicating with the chamber and adapted to communicate with the discharge ports in sequence and means for reciprocating and rotating the piston.

3. A fuel injection pump comprising a reservoir, a, cylinder extended therethrough having an intake port in direct communication with the reservoir and equispaced discharge ports, a piston in the cylinder having a chamber and a helical groove communicating therewith and adapted to communicate with the discharge ports in sequence and means for reciprocating and rotating the piston.

4. A fuel injection pump comprising a reservoir, a cylinder extended therethrough having an intake port in direct communication with the reservoir, a relief port in direct communication with the reservoir and equispaced discharge ports, a piston in the cylinder having a chamber and a helical groove communicating with the chamber and adapted to register with the discharge ports in sequence and means for reciprocating and rotating the piston.

5. A fuel injection pump comprising a uid reservoir, a cylinder extended therethrough and having one end closed so as to provide a compression chamber, said cylinder having an intake port in direct communication with the reservoir, a relief port in direct communication with the reservoir and equispaced discharge ports, a piston in the cylinder having a chamber in direct communication with the compression chamber and a helical groove communicating with the compression chamber and adapted to register with the discharge ports in sequence and means for reciprocating and rotating the piston.

VLADIMIR J. JANDASEK.

REFEREN CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain 1929 

